Red azo dye and process of making same.



UNITED sTArns rnrnu'r OFFICE.

WILHELIVL HERZBERG AND MAX BONUS, OF BERLIN, GERMANY, ASSIGNOBS-TO ACTIEN GESELLSCHAFT FU 'R ANILIN FABRIKATION, OF BERLIN, GERMANY.

BED AZO DYE AND PROCESS OF MAKING SAME.

No Drawing.

I the following is a specification;

Y varnish.

. Weight We have found that by diazotizing lan'uno-2-1nethyl-d-nitrobcnzene and combining; the diazo compound thus obtained with beta-naphthol a red azo dyestuilt' is obtained, which shows a very clear and brilliant red tint and is insoluble in alcohol and oil, as for example linseed-oil.

The new product is also distinguished by a great iastness to light and is more especially adapted for the n'ianutacture of color-lakes. "In manufacturing such color-lakes the dyestuft may be united with a suitable lake-substratun'i usually; but the lakes may also be produced in combining the formation of the dye-stud with the manufacture of the lakes.

The following example may serve to illustrate our invention, the parts being by 15.2 parts of 1amino-2-methyl- 4=-nitrobenzene are dissolved While heating in'a mixture of parts of hydrochloric acid of 12 B. and 30 parts of water. This solution is poured on ice and the diazotization performed by adding in one portion While stirring an aqueous solution of 7 parts of sodiumv nitrite. The-reaction being fin- .ished after some time the diazo solution is filtered and the filtrate introduced into a fine suspension of 15 parts of b'cta-naphthol; in order to finish the combinationv sodium carbonate is added till neutralization occurs;

The product of the reaction separates and is isolated by draining and washing with water, the dyestufi' may be employed in the form of the paste thus obtained or it may be dried and powdered. The new product thus obtained forms in the dry, and l this new Specification of Letters Patent. Pat tedAP 12, 1916, Application filed January 5, 1910. Serial No. 536,154,

pulverized shape a clear and brilliant redj powder which is insoluble in water and HI red tint is reproduced, whereas on boiling with concentrated soda-lye the color turns to a dull brown and the solution assumes a yellow color. Dilute soda-lye does not change the color. In concentrated sulfuric acid the dyestufl dissolves to a red violet solution which on the addition of ice separates rcd-orann'e flakes.

It is obviousto those skilled in the art that our present invention is not limited to the foregoing exan'ipleor to the details gii'en therein. For instance, the. production of the dyestull may be combined with the formation 01 a lake, so that the combination of the (liazo compound with the beta-naphthol and the production of the lake occur simultaneously. F or instance, the suspension of the finely divided btwnaphthol ismixed with a suitable lake substratum, such asv 5 aluminum hydrate, and into this mixture is introduced the diazo solution prepared from the 1-amino-2-methyl4-nitrobenzene.

Having nowdescribed our invention and the manner in which it may be performed What We claim is,

The hereinbefore-described monoazo dyestuff which may be obtained by diazotizin-g 1-a1nino 2-methyl-a-nitrobenzene and combining the diazo compound thus obtained with beta-naphthol, which new product is especially adapted for the manufacture of lakes and forms in the dry and pulverized shape a clear and brilliant red powder which is insoluble in water and in oil, this new dyestidl being, insoluble in alcohol at ordinarytemperature, whereas on boiling" the alcohol assumes a yellow color, and which new dyestujtt' when acted upon with concentrated soda-lye at ordinary temperature turns to rcddu'mvu, the original red tint being reproduced by adding a mineral acid, Whereas on boiling with wncen-trated sodalye the color turns to a dull. brown, the solution assumil'ig a yellow color, the tint of product not being,- altered by the action bf dilute s0da-1-ye, and this new dyeset our hands in presence of two subscribing stuff dissolving in sulfuric .acid to a red Witnesses.

violet solution which on the addition of ice WILH-ELM HERZBERG separates red-ornngo flakes a'nii which new j r 5 produet is split up by the ation of. strong BONUS reduelng agents, thus yielding para-toluy- Witnesses: I lenedian'xin besides ortho-aminonaphthol. HENRY HAsPER,

In testnnony whereof we have hereunto WOLDEMAR'HAUPi. 

